Trany fluid leak

I was driving home on the PA turnpike yesterday, and pulled over to check the contents of my trailer. I noticed a truck load of slick fluid all over the back of my TB and trailer. I looked underneath, and found that the transfer case had fluid all over the bottom. The question I have is, can a broken seal cause so much fluid leakage, or am I possibly looking at a much worse situation?

Just rolled 37,000 mi on trip

Trailer was under 400lbs

First problem with car to date

how heavy of a load were you towing and how fast? Did you pull in Overdrive? You more than likely overheated the trans and it blew out the vent. Check the trans fluid level and dont pull in OD if you did or slow down if in 3rd

What he said!

Oh, please. A Trailblazer is rated to pull something in excess of 5,000 lbs.

He says the trailer is under 400 lbs.

Granted there's some aerodynamics involved, and some wheel bearing friction, but would you drop out of OD if you had 400 lbs of people in the back seat?

Four THOUSAND pounds of trailer, maybe I could see having to downshift.

If you were pulling in a hilly area with a tall trailer and the gear ratio some trailblazers have YES I WOULD. I have seen Chevy pickups/ subs blow fluid out the vent driving to fast into a 20mph wind and they are not pulling anything. 4L60E's are not a very good tranny to pull with. You can easily go 70 in 3rd.

If this was a trans temp problem the pcm would have gone into the reduced power mode to save the unit, I don't think that is the issue here, I have pulled a 3k boat trailer up a very long steep grade and had no problems, with a 3.42 diff.

Ive seen too many blow out fluid to believe that. It even happens to blazers They have the crusie on drive to fast TC stays unlocked for too long overheats the fluid and out the vent it comes. They do have a problem with the TCC valve wearing the VB out but thats a real low mileage SUV so i doubt its that.

Troy, the pcm will not let the tcc stay locked up under any kind of slight overload, even without a trailer, cruise on, go up a slight grade at 65, most like it will down shift, for sure with a trailer. They recommend not using o/d towing to cut down the frequent up shift, down shifting. Actually the trans runs cooler in od as there is no torque multiplication thru the torque convertor, which generates more heat in fluid, plus the od clutch unit is not strong enough to handle those loads.

3rd and 4th use the same clutch pack the only difference is the 2/4 band comes on there is no heat buildup because the the TCC clutch is applied taking away the converter stall

3rd is a 1:1 ratio 4th is not there is more heat build up in 4th. when OD came out so did the TCC to increase fuel mileage and reduce heat build up because of the overdriven gear

Still the torque convertor unlocked is you biggest heat generator thats the only point I am making here, when down shift occurs under load the tcc is also disengaged hence the converotor is working again, no? Still don't see how o/d in itself generates this heat problem as long as the tcc is locked, there is no slippage in o/d. Where is this additional operating temperature created except possibly in the radiator cooler based on increased engine load in 4th. Maybe we are just on different pages here, but fluid dynamics generally would point to little or no friction from the clutches or the fluid in o/d.

I think we are on different pages. There would little more heat build up in 4th IF the TCC stays applied. the engine has to work harder in 4th thus stalling out the TC more than in 3rd which makes more heat. The TC will unlock before the Trany downshifts into 3RD if you not on the gas to much the trans will just stay in 4th and lock the TCC backup. Some cars & trucks apply the TCC in 3rd also. GM 4T65E will partially lock up at 32mph the computer watches and if it sees you getting into the gas more it will bring down the TCC slip.

I think we are on different pages. ...GM 4T65E ...
Yea, I think you mean 4L60E, as thats the tranny all 2002+ TrailBlazer/Envoys have.

OK, I messed up on what I said earlier, as I reread the post, there is very little chance that the TB would spit fluid towing 400lbs ever. I dont know exactly why it did it, but check the fluid and check it every day a few times to make sure it isnt losing fluid as you drive. If it is, go to the dealer or a tranny specialist.

I was using the 4T65E as an example of a partial lockup strategy

Troy, saw that, my 98 Lumina 3800, 4t65e operates exactly like that.

some late model 4T60E did this also. you must have a Lumina LTZ then?

some late model 4T60E did this also. you must have a Lumina LTZ then?
Yea, ex cop car 3800 with f41 suspension.

If you were looking for a LTZ around here you would be looking for a long time. how is getting to the rear plugs on that never seen one in the shop

Actually it's not bad, don't have to rock the engine forward, the smaller plenum vs the 3.1 makes it more accessible, cars pretty quick with this combo.

May not be the issue, but we jsut had a sudden tranny fluid leak. Luckily I noticed the stain on the garage floor where it's usually spotless under the '02 LTZ. Underside was covered in fluid too. Took it to the mechanic who discovered that the lines run a little too close to the catalytic converter and had basically been cooked through. had I not noticed the leak when I did, we would have been looking at a new tranny in a 3 year old vehicle.

I've heard of the same thing with a couple of envoys (who weren't as lucky as me), and we had a similar issue with our AC line melting through because it was routed too close to block.

Once we tracked down the problem it still took two days for GM to figure out which lines with which fittings to send, and because they had made modifications, we ended up having to replace the front and rear lines just to get the fittings to match up.

Basically, these things were designed by monkeys and were never meant to actually be started. Outside of a few large repair bills for design issues, it's been a pretty good truck, but we'll be unloading it soon, before all of the bells and whistles start to go haywire. I mean, if GM can't get the basics right (like routing mechanical components), I'd be crazy to think the fancy bits are designed any better.

Wasn't there a heat shield at that point mine has one, I did see this early on though and bent mine away some, though.